The present invention generally relates to skull flap fastening systems. More particularly, the present invention relates to a surgical tool which facilitates the trimming of a cranial-flap clamp used in such fastening systems.
When brain surgery is performed, it is often necessary to remove a piece of the skull to provide access to the brain. This surgical procedure is often referred to as a craniotomy. A portion of the cranial vault is removed or folded back in a flap to permit surgical access to the cranial contents, such as the brain. This is often done with a hand-held, gas-powered surgical tool similar to a small router. After a small hole is made in which the bit of the router is placed, the bit is then guided to cut out the piece of the skull required. The blade cuts a small gap so that the piece removed does not fit back into its hole exactly.
After the brain operation, the skull flap must be replaced and held in position until the skull heals. Previously, a series of matching small holes were drilled in the edge of the skull and the edge of the skull flap. Sutures were then passed through the corresponding holes and the flap secured back into the skull opening from which it was taken. However, due to the inexact fit caused by the router bit, the flap sat slightly below the surface of the skull, resulting in a depressed area visible through the skin.
Stainless steel wire was substituted for the suture material, which is stronger than the suture material, but more cumbersome. The wire was prone to failure, particularly if over-twisted, and was found to be palpated through a skin scalp if not properly buried. Also, the introduction of computed tomography (CT), demonstrated extensive metal artifacts caused by these wires. Further, the common problem of skull flap settling remained.
More recently, cranial mini-plate fixation systems were developed. While these systems have been successful, they are time consuming and very expensive.
Even more recently, alternative cranial fixation systems comprised of cranial-flap clamps having opposing closure members, often disks, in which one disk is fixed to an end of a stem, while the other is movable along the stem towards the opposing closure member to clamp the skull and bone flap together. This method is faster than any of the other methods and less expensive and time consuming than the mini-plate fixation systems.
Tools have been devised for gripping the pin or stem of the clamp, and then pressing together the disks into a clamping formation. However, the process often takes more than one tool to complete, thus requiring both hands of the surgeon. Some of the tools require calibration before use. Another disadvantage of such tools is that they require special cleaning processes due to their complicated design. Some surgeons have also found these tools somewhat complicated in use and not intuitive.
The stem of the clamp must be removed once the plates are pressed together. Without a proper tool, great care must be taken that the trimmed portions of the stem not be left in the healing wound. Traditional trimming tools, such as wire cutters, can adequately cut the pin or stem from the clamp, but result in the cut portion being projected from the clamp. This cut portion could easily project itself into an area of the wound in which it is difficult to find and extract.
Accordingly, there is a need for a surgical trimming tool which is intuitive and easy to use. The trimming tool should retain the cut stem in place until it is intentionally removed from the tool. The tool should not require special cleaning processes, nor disassembly before its next use. The present invention fulfills these needs and provides other related advantages.